Zn含量对Al-Zn-Mg-Cu合金热变形流变应力行为的影响

Influence of Zn content on flow stress behavior in the hot deformation for Al-Zn-Mg-Cu alloys

采用Gleeble-3500热模拟实验机,对3种不同Zn含量的Al-Zn-Mg-Cu合金进行等温单道次热压缩实验,变形温度为300-450℃,应变速率为0.01-10 s^（-1）,分析了热变形流变应力和本构方程。结果表明：不同Zn含量的Al-Zn-Mg-Cu合金表现出相同的变化规律,流变应力随着变形程度的增加而显著升高,达到峰值应力后,逐渐趋于平稳。可用Zener-Hollmon函数形式来描述3种不同Zn含量的Al-Zn-Mg-Cu合金的流变应力行为,当Zn/Mg比大于3时,热变形激活能先随着Zn含量的增加而增加,然后保持不变。

The isothermal single pass hot compression experiments of three kinds of Al-Zn-Mg-Cu alloys with different percentages of Zn content were conducted by Gleeble-3500 thermal simulation test machine,and the flow stress of hot compression deformation and constitutive equation were analyzed with deformation temperature of 300-450 ℃ and strain rate of 0. 01-10 s^（-1）. The results show that Al-Zn-MgCu alloys with different percentages of Zn content appear the same change rule,and the flow stress increases rapidly with the increasing of deformation degree. And then,it gradually becomes stable after reaching the peak stress. However,the flow stress behavior of Al-Zn-MgCu alloys with different percentages of Zn content can be described by Zener-Hollmon function. When the Zn/Mg ratio is greater than three,the activation energy hot deformation increases first and then remains the same with the increasing of Zn.